1. Field of the Invention
The invention relates to an electronic component and to a method of producing such a component. In particular, the invention relates to a surface acoustic wave component (SAW component) which operates with surface acoustic waves.
The SAW component has a chip with a piezoelectric substrate, with electrically conductive structures, such as interdigital transducers, interconnects and the like, provided on the chip. The SAW component further has a baseplate with external connecting elements which make contact with the electrically conductive structures on the chip, and a hermetically sealed frame, which is provided on the baseplate and within which the chip is disposed, such that the chip is disposed at a distance from the frame.
Such components generally have a high level of miniaturization and have a protective film, which provides excellent protection against physical and chemical environmental influences. However, such components require a complicated and expensive manufacturing process.
It is accordingly an object of the invention to provide an electronic component, in particular an SAW component, which overcomes the above-mentioned disadvantages of the heretofore-known components of this general type and which can be further miniaturized and which can be manufactured with a simple process at low costs. It is a further object of the invention to provide a method of producing an electronic component, such as an SAW component, which is less complex than conventional methods, while at the same time reduces the production costs.
With the foregoing and other objects in view there is provided, in accordance with the invention, an electronic component, including:
a baseplate having external connecting elements;
a chip disposed on the baseplate such that a first given space is defined between the chip and the baseplate;
the chip including a piezoelectric substrate;
electrically conductive structures being provided on the chip;
the external connecting elements electrically contacting the electrically conductive structures on the chip;
a solder frame disposed directly on the baseplate;
the chip being disposed, in accordance with a flip-chip technique, within the solder frame and spaced at a distance from the solder frame;
a film enclosing and sealing off the first given space between the chip and the baseplate, the film extending to the baseplate and defining a second given space between the solder frame and the film;
a casting compound filling the second given space between the film and the solder frame;
a cover formed of an electrically conductive material and having an edge region, the cover being applied over the chip, the casting compound and the solder frame; and
the edge region of the cover resting on the baseplate and forming a seal.
In other words, in order to achieve the object of the invention, it is suggested that the space between the chip and the baseplate is surrounded by a film, for example a plastic film, which forms a seal; that the space between the frame and the film is filled with the film and/or with a casting compound, for example epoxy resin; and that the chip together with the casting compound and the frame is protected by a cover composed of electrically conductive material, for example a copper nickel alloy, whose edge region rests on the baseplate, such that it forms a seal.
In accordance with another feature of the invention, wall surfaces and bottom surfaces bound a given space between the solder frame, the baseplate and the chip; and the film covers the wall surfaces and the bottom surfaces.
In accordance with yet another feature of the invention, a solderable layer is applied to the baseplate; and the solder frame is composed of a solderable material and is soldered to the solderable layer.
In accordance with a further feature of the invention, the cover is composed of a copper nickel alloy.
In accordance with yet a further feature of the invention, the casting compound is an epoxy resin.
In accordance with another feature of the invention, the film is a plastic film.
With the objects of the invention in view there is also provided, a method for producing an electronic component, which includes the steps of:
providing a chip fitted within a frame on a baseplate;
enclosing a first given space between the chip and the baseplate in a hermetically sealed manner by pressing a film onto the chip, except on a side surface of the chip facing the baseplate, such that the film extends at least as far as the baseplate;
filling a second given space between the frame and the film with a casting compound;
removing the film at surface regions of the film being free of the casting compound; and
applying a cover composed of an electrically conductive material on the chip, the casting compound and the frame.
In other words, the method according to the invention proposes that the chipxe2x80x94except for the side surface facing the baseplatexe2x80x94has a film, which extends down at least as far as the baseplate, pressed around it, that the space between the frame and the film is filled with a casting compound, that the film is removed in its surface regions which are free of casting compound, for example by a plasma etching and that a covering composed of electrically conductive material is applied on the chip and on the casting compound.
In accordance with another mode of the invention, the enclosing step includes cladding, with the film, wall surfaces and top surfaces bounding a given space between the frame, the baseplate and the chip.
In accordance with yet another mode of the invention, the removing step is performed with a plasma etching process.
In accordance with a further mode of the invention, the applying step includes applying, as the cover, a protective cap composed of a copper nickel alloy.
In accordance with yet a further mode of the invention, a large-area baseplate, which has a plurality of chips disposed thereon in rows, is used.
Dispensing with the protective film considerably reduces costs, and reduces the dimensions of the components. In addition, the component according to the invention is distinguished by its increased reliability since, when it is being soldered onto the baseplate, which is done using flip-chip technology, there is no risk that solder balls or bumps, which are liquid in this state, will flow into free spaces or gaps, which are present during a so-called underfilling of the component with casting compound, for example epoxy resin. Such a risk also does not exist when the component is being soldered into the respective customer circuit.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in an electronic component and a method of producing the electronic component, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.